Question

Cuantos gramos de k2cr2o7 se necesitan para preparar 250 ml de una disolución 0.125 mol/l

Answer 1

Mm K2Cr2O7 = 294 g/mol

mol = masa /Mm

M = mol soluto
       ``````````````
         V(L)

V = 25 / 1000 = 0.025 L

mol soluto = M x V(L)

mol sto = 0.125 mol /L  X  0.250 L

mol sto = 0.03125

masa = 0.03125 mol x 294 g/mol

masa = 9.1875 g

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otra forma

g = 250 mL  x    1 L   x    0.125 mol  x  294 g
                       `````````   ````````````````    ``````````
                        1000 mL      1 L             1 mol

g = 9.1875 de K2Cr2O7